Improvement in slide-valves



UNITED STATES PATENT Grinch.

ANDREW BUCHANAN, 0F NEW YORK, N. Y.

IMPROVEMENT IN SLIDE-VALVES.

Specification forming part of Letters Patent No. 411.394, dated September 27, 1864; antedated September 16, 1864.

To all whom t may concern:

Beit known that l, ANDREW BUCHANAN, of the city of Brooklyn, in the county of Kings and State of New York, have invented a new and Improved Means of Relieving Slide-Valves and their Seats of Friction; and l do hereby declare that the following is a full, clear, and exact description ofthe same, reference being had to the accompanyingdrawings, forming part of. this specification, in Whichv Figure l is a central longitudinal section of the valvechest and slide-valve of a steam-engine, illustrating my invention. Fig. 2 is a transverse vertical section of the same. Fig.-

3 is a plan of the same with the cover of the chest removed to expose the interior to view. Fig. 4 is a side View of the principal parts of the device for relieving the valve and seat. of friction.

Similar letters of reference indicate corre spending parts in the several figures.

This invention consists in the support of a slide valve in such manner as to remove the pressure and friction as much as practicable from its face and seat by means of one or more gibs attached to the valve, and Working on a stationary slide or slides attached to the valve seat or chest, the faces of the said gib or gibs t and-slide or slides being of harder metal or material than the body of the said gib or gibs and slide or slides.

It further consists in a certain construction of the said gib or gibs whereby the valve is lifted from or drawn back entirely out of contact with its seat Whenever the pressure is shut oli' and the engine still kept running with the valve face and seatvdry, as in the case of a locomotive descending a grade or running into a station, and the valve is thereby caused to run without friction.

To enable those skilled in the art to make and use my invention, I will proceed to describe its construction and operation.

A is the valve-chest, B the valve-seat, and C the slide-valve, all constructed in the usual manner. D is a stationary slide arranged carefully within and lengthwise of the valvechest. E is a gib attached to the back ofthe valve, to work on the said slide. The slide is composed of a cast-iron bar having its upper surface chilled, and extends nearly the whole length of the chest over and out of contact with the back of the valve, and has made in the saine piece with or otherwise attached to it two feet, D D', which are bolted to the cylinder or bottom of the valve-chest at the ends of the seat. The chilled upper surface of the said slide is ground to a perfectly-flat face, and is perfectly parallel with the face of the valve-seat.

The gib E is made of steel, and is secured to the back of the valve and upon the upper surface of the slide D by means of two metal strappieces, F F, which pass over its back and are bolted or otherwise secured to the back of the valve, the said straight pieces being so constructed as to confine the gib laterally, but as to permit of a certain amount of adjustment ot' the valve perpendicularly to its seat by means of two set-screws, c rt, which screw through the backs of the said straps and bear upon the back of the gib. rlhe turned up ends b b of the gib f it against the outer faces of thc said strap-pieces, as shown in Fig. 1, and thus confine the gib to the valve in a longitudinal direction, and so compel the gib to move with the valve in the operation of the latter. The under surface of the gib is faced to fit and smoothly upon the surface of the slide. l

The set-screws a a are so adjusted to press upon the gib as to transfer as near as possible the whole of the pressure produced by the pressure of the steam on the back of the valve from the valve to the gib, just allowing the valve to work in steam-tight contact with the seat without any appreciable friction. The faces of the gib and slide, being much harder than those of the valve and seat, will wear for a long time without allowing the valve to bear hard upon its seat and be subject to wear; and when any leakage between the valve and sea-t is discovered either by taking off the cover of the chest A or by removin gplugs provided therein over the screws for the insertion of a suitable instrument, and giving the screws a a a very slight turn backward, the valve is letdown into close contact with its seat.

To provide for the lubrication of the gib and slide, there is drilled into the slide from one end a passage, c, the open end of which is afterward closed byinserting a steam-tight plug, d, Fig. l. and a longitudinal slot, c, out 0I' otherwise formed in the face of the slide, forms a communication between the said passage and the said face. The length and position of this slot is such that it extends nearly the whole length of that portion of the face of the slide which is not uncovered by the gib in the working of the valve. Near the plugged portion of the passage c there is inserted into the slide D a steam tight tube, f, which forms a communication between the passage c and a grease cup, G, which is screwed intothe cover of the steamchest. As the gib works steam-tight upon the slide, the steam is excluded from the passage c, and grease from the cup G will be forced into the said passage and into the slot e, and the face ofthe gib will be thereby supplied with grease, which will be carried by the movement of the valve a-nd gib over the whole of the inipinging surfaces of the giband slide.

To provide for the raising oi' the valve from its seat when the steam is shut oft' from the steam-chest,1 propose to make the t'ace of the gib very slightly rounded or arched length wise, as shown at i t' in Fig. 4, and to adjust the valve so that when there is no pressure on its back the valve will be raised or held back from itsseat a distance equal to the versed sine of the are By this means, when the engine is running without steam and ith the valve dry, as in the case of a locomotive descending a grade or running into a station, the valve will work without any friction, and in this way the most common cause for the rapid wearing of locomotive valves and seats will be Obviated. When the steam is admitted, its pressure on the back of the valve being transferred to the gib springs the ends of the gib downward and brings its face iiat down upon the face of the slide.

Instead of a single gib and slide, there may be two gibs and two slides arranged parallel with each other, to operate in the manner descr'ibed. The gibs and slides, instead of being arranged over or at the back of the valve, may be arranged at the sides thereof or iiush with or below the face of thevalve, and the slides may be formed or portions of the valve chest or seat.

What I claim as my invention, and desire to secure by Letters Patent, is-

l. The employment, for relieving the face and seat of the slide-valve of friction, of one or more gibs, E, and slides D, applied and oper ating substantially as herein specified.

2. The lubrication of such gibs and slides by means of a passage, c, and slot e in the slide communicating with a grease-cup, G, outside of the valve-chest, substantially as and for the purpose herein specified.

3. Making the face or faces of the gib or gibs of rounded or arched form longitudinally, substantially as and for the purpose herein set forth.

ANDREW BUCHANAN.

Witnesses:

HENRY T. BROWN, GEO. W. REED. 

